Question

The main component of bleach is sodium hypochlorite, \(\mathrm{NaOCl}\), which consists of sodium ions, \(\mathrm{Na}^{+}\), and hypochlorite ions, \(\mathrm{OCl}\). What products are formed when this compound is reacted with the hydrochloric acid, HCl, of toilet bowl cleaner?

Short answer

The products are sodium chloride, chlorine gas, and water.

Step-by-step solution

Identify the Reactants

The reactants in this chemical reaction are sodium hypochlorite \( \mathrm{NaOCl} \) and hydrochloric acid \( \mathrm{HCl} \).

Write the Balanced Chemical Equation

When \( \mathrm{NaOCl} \) reacts with \( \mathrm{HCl} \), the products are sodium chloride \( \mathrm{NaCl} \), chlorine gas \( \mathrm{Cl_2} \), and water \( \mathrm{H_2O} \). The balanced chemical equation is: \[ \mathrm{NaOCl + 2HCl \rightarrow NaCl + Cl_2 + H_2O} \]

Verify Conservation of Mass

Check that each element has the same number of atoms on both sides of the equation. We have 1 sodium, 1 oxygen, 2 chlorine, and 2 hydrogen atoms on each side, thus conserving mass.

Key concepts

Balanced Chemical Equation

A balanced chemical equation represents a chemical reaction with the same number of each type of atom on both the reactant and product sides. This reflects the conservation of mass principle, where mass cannot be created or destroyed in a chemical reaction.
To balance a chemical equation, you might need to determine the correct coefficients that equalize the number of atoms for each element involved in the reaction.
In the reaction of sodium hypochlorite with hydrochloric acid, the balanced equation is:\[\mathrm{NaOCl + 2HCl \rightarrow NaCl + Cl_2 + H_2O}\]

• Each side of the equation has 1 sodium (Na), 2 chlorine (Cl), 1 oxygen (O), and 2 hydrogen (H) atoms.
• This ensures both mass and charge are balanced.

Balancing equations is essential for correctly understanding and predicting the outcome of chemical reactions.

Sodium Hypochlorite

Sodium hypochlorite (\(\mathrm{NaOCl}\)) is a compound commonly used as a bleach and disinfectant. It consists of sodium cations (\(\mathrm{Na^+}\)) and hypochlorite anions (\(\mathrm{OCl^-}\)). These ions are responsible for its chemical activity.
Sodium hypochlorite functions as an oxidizing agent, meaning it can accept electrons from other substances, often resulting in reactions that lead to a change in the oxidation state of these substances.
In household bleach, sodium hypochlorite is typically found at a concentration of 3-8% and is effective at:

• Disinfecting surfaces
• Bleaching clothes
• Sanitizing water

Understanding sodium hypochlorite's reactivity helps us predict how it interacts with other compounds.

Hydrochloric Acid

Hydrochloric acid (\(\mathrm{HCl}\)) is a strong acid formed from hydrogen and chlorine. It is widely used in industrial processes and household cleaners, such as toilet bowl cleaning products.
As a strong acid, it completely dissociates in water into hydrogen ions (\(\mathrm{H^+}\)) and chloride ions (\(\mathrm{Cl^-}\)).
Hydrochloric acid's properties make it effective for:

• Removing rust and scale from metals through chemical reactions
• Neutralizing alkaline substances
• Acting as a catalyst in various chemical syntheses

Its reactivity also allows it to interact with compounds like sodium hypochlorite, leading to significant chemical transformations.

Conservation of Mass

The conservation of mass is a fundamental principle in chemistry stating that mass is neither created nor destroyed in a chemical reaction. This reflects the atom's integrity, where the number of each type of atom remains constant from reactants to products.
In our example of sodium hypochlorite reacting with hydrochloric acid, the equation:\[\mathrm{NaOCl + 2HCl \rightarrow NaCl + Cl_2 + H_2O}\]demonstrates the conservation of mass:

• There is an equal number of each type of element on both sides of the equation.
• This balance verifies that no atoms are lost or gained, only rearranged.

Conservation of mass is crucial for accurately predicting the products and quantities formed in a chemical reaction. Understanding this concept is essential for engineering, chemistry, and many scientific disciplines.